Revenues Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	$ 862,743	$ 1,109,584
Transportation expenses	60,502	49,139
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	862,743	1,109,584
Transferred over Time
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	0	0
North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	595,177	826,660
North Region [Member] | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	595,177	826,660
North Region [Member] | Transferred over Time
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	0	0
South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	267,566	282,924
South Region [Member] | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	267,566	282,924
South Region [Member] | Transferred over Time
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	0	0
Crude oil sales
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	773,770	911,118
Transportation expenses	50,400	41,600
Crude oil sales | North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	581,869	764,333
Crude oil sales | South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	191,901	146,785
Natural gas sales
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	88,973	198,466
Transportation expenses	10,100	7,500
Natural gas sales | North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	13,308	62,327
Natural gas sales | South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	75,665	136,139
Operated properties | Crude oil sales
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	628,106	722,152
Operated properties | Crude oil sales | North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	448,930	585,605
Operated properties | Crude oil sales | South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	179,176	136,547
Operated properties | Natural gas sales
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	83,894	176,159
Operated properties | Natural gas sales | North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	11,588	51,461
Operated properties | Natural gas sales | South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	72,306	124,698
Non-operated properties | Crude oil sales
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	145,664	188,966
Non-operated properties | Crude oil sales | North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	132,939	178,728
Non-operated properties | Crude oil sales | South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	12,725	10,238
Non-operated properties | Natural gas sales
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	5,079	22,307
Non-operated properties | Natural gas sales | North Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	1,720	10,866
Non-operated properties | Natural gas sales | South Region [Member]
Disaggregation of Revenue [Line Items]
Crude oil and natural gas sales	$ 3,359	$ 11,441